This relates generally to electronic devices, and more particularly, to electronic devices with displays.
Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user.
Liquid crystal displays contain a layer of liquid crystal material. Pixels in a liquid crystal display contain thin-film transistors and electrodes for applying electric fields to the liquid crystal material. The strength of the electric field in a pixel controls the polarization state of the liquid crystal material and thereby adjusts the brightness of the pixel.
Substrate layers such as color filter layers and thin-film transistor layers are used in liquid crystal displays. In an assembled display, the layer of liquid crystal material is sandwiched between the thin-film transistor layer and the color filter layer. The color filter layer contains an array of color filter elements such as red, blue, and green elements and is used to provide the display with the ability to display color images. The thin-film transistor layer contains thin-film transistor circuitry that forms the thin-film transistors for the array of pixels. The pixels contain capacitors to store data values between successive image frames.
The array of pixels is loaded with data using vertical data lines. Horizontal control lines called gate lines are used in controlling the circuitry of the pixels in the array, so that pixels display the data provided on the data lines. With a typical arrangement, each gate line is associated with a respective row of pixels. A frame of image data may be displayed by asserting each of the gate lines in the display in sequence, so that rows of data can be loaded into the display pixels from the data lines.
The signals on the gate lines are produced by gate driver circuitry. The gate driver circuitry may be implemented using blocks of thin-film transistor circuitry that run along the left and right edges of the thin-film transistor layer and thereby limit the minimum sizes of the left and right edges.
Other types of displays such as organic light-emitting diode displays also have vertical data lines and horizontal control lines. The pixels in an organic light-emitting diode display contain light-emitting diodes that produce light and contain thin-film transistors that control the amount of light that is produced by the light-emitting diodes. The vertical data lines may be used to distribute data to the pixels and the horizontal control line may control the loading of data from the vertical data lines onto the gates of drive transistors that control the outputs of the light-emitting diodes. This type of display may also have blocks of thin-film transistor circuitry along its edges.
For aesthetic reasons and to save space in an electronic device, it may be desirable to reduce the size of the borders of a display. The presence of thin-film driver circuitry along the edges of the display limits the minimum achievable border size for a display. If care is not taken, a display will have larger inactive borders than desired.
It would therefore be desirable to be able to provide improved displays for electronic deices such as displays with minimized borders.